Applicant has, for some time, been selling a pressure-measuring arrangement comprising:
a pressure sensor having a base and an associated diaphragm with strain gages deposited thereon; PA1 a header of insulating material with leads and with an oil filler neck, PA1 said header of insulating material having the base mounted thereon, and PA1 said leads making electrical contacts to the strain gages; PA1 a metal body having a first central recess in a first cross-sectional surface, a second central recess in a second cross-sectional surface facing away from the first cross-sectional surface, and a hole connecting the first recess with the second recess, PA1 said first cross-sectional surface being tightly joined at its edge to the header of insulating material, and PA1 said first recess accommodating the substrate and PA1 a metallic separating diaphragm fitted in the second recess and closing the latter at its edge; and PA1 an oil fill in the recesses and in the hole. PA1 a pressure sensor having a base and an associated diaphragm with strain gages deposited thereon; PA1 a header of insulating material with leads and with an oil filler neck, PA1 said header of insulating material having the base mounted thereon, and PA1 said leads making electrical contacts to the strain gages; PA1 a metal body having a first central recess in a first cross-sectional surface, a second central recess in a second cross-sectional surface facing away from the first cross-sectional surface, and a hole connecting the first recess with the second recess, PA1 said first cross-sectional surface being tightly joined at its edge to the header of insulating material, and PA1 said first recess accommodating the substrate and diaphragm without touching them; PA1 an electrically conductive foil having an opening, PA1 said foil being disposed in the first recess as close as possible to, and covering but not touching, the strain gages and connected to ground; PA1 a metallic separating diaphragm fitted in the second recess and closing the latter at its edge; and PA1 an oil fill in the recesses and in the hole.
diaphragm without touching them;
This pressure-measuring arrangement, which is in public use, is in need of further improvement regarding its sensitivity to electromagnetic interference and to charge influences from the oil fill and regarding its long-term stability.